A persistent pack of protesters has become part of the Friday afternoon scene at the corner of Tamalpais Avenue and Third Street in San Rafael.

As they’ve done periodically since February, the demonstrators — part of an online San Rafael historical preservation group — marched Friday against demolition of the city’s former train depot at the site now occupied by Whistlestop senior center.

“We don’t want the depot destroyed,” said Cynthia Landecker, who manages the preservation group. “I’m not saying don’t knock down any historical building, but this is the entrance to the city.”

The group started the protests when Whistlestop officials in January went to the city with a proposal to expand their center into a five-story affordable senior housing and services center by 2017.

Public hearings were held and community members expressed concern with the size of the proposed building, its design and parking layout.

Officials with the nonprofit senior center, who own the property the depot is situated on, went back to the drawing board and earlier this month formally submitted a new design that addressed community concerns. The $25 million plan includes a senior services center, 41 studio and one-bedroom apartments, a 1,250-square-foot public plaza, a cafe and a parking garage.

The center has operated out of the site since 1971.

The depot was built 85 years ago. But the site has served as a train station since 1884 and was a crucial component of developing San Rafael into what it is today, Landecker said.

“We want to save the train station, because that’s what it is — the existing building is related to the past function of the first station there in 1884,” she said. “And its connection to San Francisco is so vital. The whole development of the city is rooted in that spot.”

Landecker and Amy Likover, another resident dissatisfied with the possibility of the depot’s demolition, said they support the mission of Whistlestop but believe it could be better situated at another location.

“We want to help find a more appropriate site for seniors to live that’s not at the crossroads of the 101 (freeway), the transit center and Second Street,” Likover said. “It’s an opportunity to create a welcome center.”

Whistlestop CEO Joe O’Hehir has said expanding at the site is the cheapest option for the group as it already owns the property. The group is also on a deadline, as they’re hoping to learn what they’re doing in regards to expansion before the Sonoma-Marin Area Rail Transit commuter train, which has tracks adjacent to Whistlestop, rolls into operation beginning next year.

“Our job here is to think of the welfare of seniors,” O’Hehir said. “It’s the foremost of everything we’re doing. We want to ensure we can continue the same programs and serve Marin seniors.”